Specific sources of pollution that can be identified are called
a. point sources.
b. nonpoint sources.
c. runoff.
d. sewage.

Although there are a limited number of amino acids many different types of proteins exist because..

What sentence best supports the statement that hormones are involved in the regulation of homeostasis? a. the hormone erythropoeitin increases the production of red blood cells when oxygen levels are low. b. the hormone oxytocin promotes labor contractions of the uterus during childbirth. c. the hormone melatonin induces sleep and its production is slowed by exposure to light. d. the hormone cortisol suppresses the immune system and is produced when the body is under stress.

Which of the follow describes a disadvantage secondary sources have compared to primary sources?